I am seeking support from the Preventive Oncology Academic Award Program in order to acquire new skills that will permit me to become an independent investigator in the field of cancer etiology and prevention. My training is in general chronic and infectious disease epidemiology. I would like to build upon that background by acquiring further training in cancer biology, molecular biology, and biostatistics. My research program will focus on the epidemiology and primary and secondary prevention of hepatocellular carcinoma (HCC). l have proposed three research projects as part of this application. The first one, Primary Hepatocellular Carcinoma in Chinese Women, is a pilot study of my own design which will form a foundation for my future research-In cancer prevention. The two other proposed research projects involve the use of data from two large prospective cohort studies and a randomized trial of secondary prevention of HCC. The three projects together involve three different phases of prevention research. The first seeks to identify gender differences in HCC risk factors which may be used to inform the design of interventions in the future. Risk factors for and prevention of HCC in women has been largely ignored in both epidemiologic and clinical investigations. The second project targets a specific risk factor--aflatoxin B1--and focuses on improving understanding of the variability of exposure to this agent in a high-risk area. This project will produce valuable data for use in both environmental (aflatoxin control) and chemopreventive interventions. The third project uses data from a randomized trial of secondary prevention of HCC in order to estimate parameters of the natural history of the disease which can be used in future research on secondary prevention methods, especially in such important areas as determining the optimal timing of screening tests. My goal in this application is to examine the complex problems that cannot be solved satisfactorily by standard techniques. Alternatives to unsatisfactory standard techniques may be found in both biological and statistical methods which can allow the epidemiologist to measure more precisely the parameters of interest. Moreover, the experience and knowledge gained in the process of searching for these solutions will also form the foundation for further research ideas and projects in cancer prevention.